The invention is a significant improvement over my U.S. Pat. No. 2,865,102, granted Dec. 23, 1958. In this patent, a "research" device is disclosed for fabricating prostheses comprising a holder upon which a maxillary cast is mounted, and positioning means are employed whereby the cast may be positioned for mounting on the holder. The positioning means is provided with knife edge for providing co-level support to specific points in the hamular notches of the maxillary cast and a sliding metal strip which extends normal to the knife edge for supporting the anterior midpoint portion of the maxillary cast. The positioning means may take the form of a plurality of points with two of the points being co-level for engagement with the points in the hamular notches of the cast.
In the prior art device which utilized fixed anatomical points for mounting the cast, the three points (hamular notches and mid point on the crest of the ridge at the front of the cast) were all positioned at the same elevation. Although my earlier device embodied some flexibility, such as in vertically and angularly positioning of a curved or flat template, considerable time and skill as well as experience was still required to fabricate dentures.
With the apparatus of my present invention, less skill and time are required. Moreover, with the improved apparatus, greater precision is achieved and the apparatus lends itself to wider use. The resulting cast orientation and/or setting of teeth are replicable at all times.
As a result of my development and research work with the aforesaid device, it was recognized that due to varying length of the anterior teeth, the three points are not on the same plane. This led to my further improvement of utilizing a spear-like element to raise or lower, as well as translate the tray and occlusion rim that holds the maxillary cast. In this arrangement of the device, the front or anterior point thus became independent of the rear or posterior points which are also capable of being raised or lowered. Such specifications further led to my uniquely movable knife edge assembly and mounting sleeve arrangement. When the mounting sleeve, attached to a tray with occlusion rim is impaled on the spear like element, the anterior point exhibits a 3.degree. slope from the knife edge.
The anterior point resides at the mid-saggital plane of one's head. The replicability of results enables one to reproduce the exact fabrication of lost dentures after making duplicate casts from the original casts. The duplicates are maintained by the dentist or laboratory technician. In another application of my invention, it will be readily recognized that an orthodontist can observe his or her progress and progression in the redirecting and straightening of crooked or otherwise protruding teeth.
It is, therefore, the principal object of the invention to provide a device whereby an improved apparatus and method may be used in the fabrication of various types of dental prostheses.
Another object of the invention is to provide an improved apparatus or device which is simple in operation and yet extremely precise in its function and applicability to dental prostheses.
Yet a further object of the invention is to provide a device which can be transferred to an articulator with minimum effort, but with exact relationship.
It is yet another object of the invention to enable my improved device to be readily adapted for use on any dental articulator with or without the requirement of an intervening mounting plate or unit.
Accordingly, these and other objects of my invention will become readily apparent from a reading of the disclosure when taken in consideration of the accompanying drawings.